gc: simplify --cruft description

Remove duplicate "loose objects".

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-gc.txt

@@ -56,8 +56,7 @@ be performed as well.
 
 --cruft::
 	When expiring unreachable objects, pack them separately into a
-	cruft pack instead of storing the loose objects as loose
-	objects.
+	cruft pack instead of storing them as loose objects.
 
 --prune=<date>::
 	Prune loose objects older than date (default is 2 weeks ago,